Lipid turnover in Schizochytrium supports a preferential degradation of saturated fatty acids and a reservation of polyunsaturated fatty acids. In this study, multiple omics were utilized at different cultivation stages of Schizochytrium sp. S31 to reveal the mechanism of lipid turnover. During the lipid turnover stage, palmitic acid content decreased from 41.18% to 21.33%, while docosahexaenoic acid content increased from 31.20% to 50.43%. The lipidomic analysis showed that the lipid turnover mainly happened to saturated triacylglycerol accompanying with an increased level of phosphatidylinositol and phosphatidylcholine. The transcriptomic result further indicated that the differential expression genes related to the fatty acid degradation pathway were significantly increased, and the formation of phospholipids from diacylglycerol was enhanced. Finally, genomic sequencing and genetic engineering proved that the characterized triacylglycerol lipase might participate in the preferential hydrolysis of saturated fatty acids during lipid turnover. These results would not only enrich the current knowledge regarding the lipid turnover phenomenon but also contribute to the production of high-quality single cell oil from microalgae.

裂殖壶菌中的脂质更新支持饱和脂肪酸的优先降解和多不饱和脂肪酸的保留。在这项研究中，在裂殖壶菌的不同培养阶段利用了多种组学技术sp。S31揭示脂质转换的机制。在脂质转换阶段，棕榈酸含量从41.18％降低到21.33％，而二十二碳六烯酸含量从31.20％增加到50.43％。脂质组学分析表明，脂质周转主要发生在饱和的三酰基甘油上，同时磷脂酰肌醇和磷脂酰胆碱的含量也增加。转录组结果进一步表明，与脂肪酸降解途径相关的差异表达基因显着增加，并且由二酰基甘油形成的磷脂得到增强。最后，基因组测序和基因工程证明，表征的三酰基甘油脂肪酶可能​​参与脂质周转过程中饱和脂肪酸的优先水解。